A couple of days ago (June 2018) I was startled by the bright red colour of the seawater at Mill Bay BC. These blooms of dinoflagelates (a type of plankton) are population explosions that occur in spring and summer. Some dinoflagellates become so numerous that the water becomes a rusty-red. There is a red oil drop containing pigment in each organism that reflects to make the red colour. The small red spots in the organism, when added to a population bloom countless numbers of similar organisms give seawater the characteristic colour that makes up a red tide.
A dinoflagellate is a single celled organism and most species live free in sea water. Most have two whip-like flagella – one to drive the organism forward and the other to make it rotate. This allows the organism to adjust its orientation and vertical position to make the best use of light for photosynthesis.
This organism feeds on bacteria, diatoms and other dinoflagellates. When organism is caught it exudes some of its cytoplasm to engulf the prey. They prey is then digested externally before being retracted back into the body.
I took these images through my microscope with a digital camera. This dinoflagellate is a Protoperidinium sp. Dinoflagellates cannot produce their own food but are predators who catch and eat other small organisms. They in turn are prey for copepods and bottom dwelling suspension feeders such as hydroids.
In Saanich Inlet a localized bloom became very evident when persistent wind appeared to concentrate water on the lee shore. The water looked very rusty red but at times the sun made it almost glow bright red.
These blooms (Harmful Algal Blooms) can become dangerous because the physiology of other organisms can be affected. The organisms produce a potent neurotoxins as part of their metabolism. Filter feeder organisms (such as clams, mussels, oysters) can concentrate these toxins. If humans eat these organisms they can become very ill, or even die from paralytic shellfish poisoning.
Beach goers can be affected even if they do not eat affected organisms. There have been cases where blowing wind picked up dried organisms with the toxins and persons who breathed them in or ingested them were affected with inflamed eyes and asthmatic-like symptoms.
Until yesterday I was unaware of these tiny organisms that I found in a trawl with my plankton net in the Georgia Strait between Vancouver Island and the mainland. Looking at them under the microscope, at first I thought that they were very young fish but experts in microscopic life made a positive identification as being Oikopleura sp.
They are urochardates known as larvaceans, related to the tunicates (sea squirts). Although they are technically invertebrates they have a body plan that resembles a fish with a backbone. These animals have one of the smallest DNA genome sequences of any animal. They live a very short lifespan of only a few days. They release eggs and sperm into the ocean to reproduce. Living only a few days they can appear in large numbers becoming an important component of the food chain.
This example was squeezed out of the water drop when I lowered the cover slip onto the glass microscope slide. It is laying alongside the edge of the glass cover slip and I just happened to notice it when I was scanning the slide for interesting targets.
They carry captured debris in tiny nets which, when they get clogged, are abandoned and eventually sink to the bottom. Carrying remnants of their food (bacteria and phytoplankton) this moves the Carbon from the atmosphere sequestered by phytoplankton as biomass back into the chemical form. In the process they become an important food source for larger organisms. These ‘nets’ are a significant portion of the ‘white snow’ that is observed in the water column slowly sinking to the ocean bottom.
A couple of days ago I used my plankton net and found this marine water mite in the trawl sample. I have not seen one of these before. I don’t know if they have been present but unnoticed in my samples or if it has just appeared.
This organism is closely related to the much more common and numerous freshwater relatives found in ponds and streams. The scientific literature on this species is not easy to find on the internet. I believe that it is from the family Pontarchachnidae which is the only family of the Hydrachnidae occurring in the marine environment.
Michael W. Konrad published a highly illustrated book of the marine plants and animals that can be found clinging to docks, floats, and pilings on the Pacific coast. The book surveys many organisms that are easily visible to the naked eye but to the joy of the micro-naturalist he also includes the microscopic world.
I highly recommend it to west coastal micro-naturalists. It is competently written, very informative and well illustrated. Many of the organisms will be encountered on field trips and some are suitable for viewing under a microscope. It makes good general reading on the subject.
The book was published in 2013 by Science Is Art at Sausilito CA. ISBN 978-0-9832590-0-8 paper bound. The author is Michael W. Konrad. It should still be available from book sellers online.
This is a good starter reference book to diatoms. They are tiny creatures that can be easily seen under the microscope. Its fun to see them but much more rewarding to be able to identify them. I capture my samples with a plankton net.
Diatoms are excellent subjects for study by amateurs under the microscope. They occur in lots of locations so besides being beautiful they are easily found in marine and freshwater settings. Diatoms are recognizable by their silca-based ‘shells’ called frustules.These are in two halves, and contain the living organism.
A good guide to diatoms is William Vinyard’s book which is available from online book dealers. This book will bring pleasure to the viewing of diatoms because it gives an easily followed identification index. It also provides lots of background on the biology of diatoms.
Some Images of Marine Diatoms from the Georgia Strait British Columbia
Foraminifera are simple organisms which, when alive, protrude pseudopodia through tiny pores in a rigid calcareous test or shell. This shell can be a single chamber or can be composed of multiple chambers. Most are marine, and can be either bottom-dwelling or floating plankton.
The accumulations of their dead shells become part of the sediment column on the bottom of the ocean. Under the microscope these shells are intricate and beautiful. They tell the story of the conditions under which they lived. They are not easy to locate in our area – but turn up as micro-fossils in sediment on the sea floor.
The shells are particularly beautiful and intricate. Each species can be identified from particular features produced in this structure. Mainly marine, both benthic (bottom dwelling) and planktonic (floating in the water column). They are little known to amateur micro-naturalists. Once they are discovered, they create a fascination which is hard to shake.
Close proximity to the sea provides many opportunities for the Micro-Naturalist to enjoy endless viewing of spectacular subjects. Plankton is one of those topics.
How to do it?
I use a small student-grade plankton net launched by hand from the shore on a line to gather samples. I view them while the subjects are still fresh. By capturing images of the most interesting subjects I was able to research and identify the organisms from reference texts.
Where to get them?
The waters around Vancouver Island BC are easy sources of phytoplankton and zooplankton. With very little effort you can get fantastic forms of microscopic life into view. Even the sand is worth studying. But you could find them in a lake, a pond or pool.
The variety and quantity of organisms is different each time. There are examples of both phytoplankton and zooplankton in the samples. Care in handling the raw sample ensures that few of the organisms are damaged and of course only a small drop of water from the sample is examined at any one time (so the sample does not need to be very large).
Identification of Organisms
I refer organisms that I cannot identify to the Amateur Microscopy Facebook group where experts assist with identification down to the genus, and sometimes even to the species level. By keeping a lab notebook I keep records of the organisms I encounter, and make notes when they are identified. This provides a reference for later use when examples of the organisms are encountered again.
Linking up other like-minded amateur users of microscopes is a major goal of this website. Scattered the length of Vancouver Island are amateur microscopists working alone on their hobby. Imagine an informal network linking us all up together – and even hosting periodic coffee meet ups where we can all get to know each other. Maybe some day we will host a technical meeting – with speakers – its possible!
What Is a Micro-Naturalist?
A micronaturalist is simply a naturalist who is interested in using a microscope to access the small world that forms the basis of all life. “Take a field trip without leaving the room with a microscope” is our tagline.
The idea is to learn from each other, trade information, and even build friendships that generate projects. We could, as a group, create useful tools for others based on the knowledge we are accumulating. I’d like to think that we are going to inspire others to join us in this activity.
Meet Up with Us
If you are interested in linking up with us – please send a message to microscope (at) shaw.ca expressing an interest. We are a friendly, respectful, supportive and positive group who would like to include anyone interested in microscopy.